Silicon-graphene nanocomposites for electrochemical applications

Abstract

A nanographitic composite for use as an anode in a lithium ion battery includes nanoscale particles of an electroactive material; and a plurality of graphene nanoplatelets having a thickness of 0.34 nm to 5 nm and lateral dimensions of less than 900 nm, wherein the electroactive particle has an average particle size that is larger than the average lateral dimension of the graphene nanoplatelets, and the graphene nanoplatelets coat at least a portion of the nanoscale particles to form a porous nanographitic layer made up of overlapping graphene nanoplatelets.

Description

INCORPORATION BY REFERENCE[0001]All patents, patent applications and publications cited herein are hereby incorporated by reference in their entirety in order to more fully describe the state of the art as known to those skilled therein as of the date of the invention described herein.BACKGROUND OF THE INVENTION[0002]This invention relates to graphene nanoplatelet composites with electroactive materials, and electroactive materials coated with graphene nanoplatelets. The graphene nanocomposites are useful as battery materials.[0003]Lithium-ion batteries are being pursued for a variety of applications including electric or hybrid electric vehicles (EV & HEV), consumer electronics, grid energy storage systems and distributed power generation units. The success of LIB in such markets strongly depends on the cost, energy density, power capability, cycle life, and safety of the battery cells, which are largely dominated by the electrode materials used. While LIB technologies have advance...

AI Technical Summary

Benefits of technology

[0060]2-dimensional and flexible graphene nanoplatelets are introduced into the Si anode structure to accommodate the volume change of Si particles and maintain the integrity of the electrode during cycling. The face contact between graphene nanoplatelets and Si particles is mo

Problems solved by technology

While LIB technologies have advanced significantly since their first commercialization in the early 90's, they are not keeping pace with the ever increasing demand for batteries with higher energy storage capacities.

This target cannot be met with current LIB chemistries, especially with graphite as the anode.

Nevertheless, replacing traditional graphite anode materials with Si has proven to be very challenging.

Two major barriers have hindered the development of Si-based anodes for commercial applications, especially for use in EV batteries:Poor cycle life.

Si tends to pulverize during cycling as a result of substantial volume change (up to 400%) during charging/discharging of the batteries, which in turn leads to the loss of electrical contact or even disintegration of both Si particles and the electrode coating.High synthesis cos

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